In a power distribution system that supplies power with multiple loops, each loop is provided with a circuit breaker, and a circuit breaker which is typically switch-off and acts as an interconnection switch or a loop switch is provided between loops. If a loop therein disconnects due to power failure, the circuit breaker acting as an interconnection switch or a loop switch will close so as to ensure normal operation and power supply of the multi-loop power system mounted with the circuit breakers and of the load connected to the circuit breakers.
In practical application, a circuit breaker is required to perform some auxiliary functions aside from its normal operation functions so as to guarantee safety, for example, mechanical interlocking between two or more circuit breakers is required, aside from the electric interlocking between the set of circuit breakers having circuit breakers acting as interconnection switches or loop switches.
To implement interlocking between the set of circuit breakers, the mechanical interlocking methods and devices employed in the prior art are key interlock, leverage interlock and wire rope interlock, which are named by motion translation mediums. The mechanically interlocking circuit breaker means employed in current key interlock has a disadvantage that in-field manual operation is required to unlock the interlock, which can not satisfy the demand of automatic control.
In the prior art, some mechanically interlocking circuit breakers use the leverage interlock or wire rope interlock means or their combination with the key interlock means, disadvantage of which means lies in that only interlock between two circuit breakers can be implemented, and for interlock between three circuit breakers, random combination can not be implemented. Besides, under the current technical state, the known interlocking means for circuit breakers still have some drawbacks or performance deficiencies, though they can provide operating functions as required.
An invention patent No. 97125954.2 discloses a set of switches with interlock means, which discloses specifically the following technical features for this known mechanical interlock means: each switch has an elastically supported rocker, each rocker being operatively connected to means capable of locking a corresponding switch, each switch having a drive means connected to two ends of two cables. Since this known rocker that forms a mechanical interlocking means with cables is elastically supported, it is highly demanding on mounting and adjustment, with relatively poor repetitive positioning precision and vibration-proof performance. For a rocker directly connected to a trigger, its poor repetitive position precision and vibration-proof performance greatly affects the working reliability and robustness of the switches.
Specifically, since the force for locking a trigger in the prior art is directly the tensile force of a cable, movement of the rocker is realized by axial movement of the wire ropes inside the cable, thus it is highly demanding on the positioning precision of the cable member, which causes problems such as difficulty for adjustment, low productivity and high processing cost. Besides, in use, it is inevitable that connection of wire ropes becomes loose and deformed and that wire ropes become lengthened under tensile force. These problems directly impair positioning precision of the cable member, make locking operation out of order, and greatly affect the product's safety, reliability, robustness and service life.